Classic BAT vs. Audio Research

Thanks for the insight, gpgr4blu. Right now I have the opportunity to buy a used ARC Reference 150 for $7500, or a pair of BAT VK-150SE amps for $6K. I've always been a solid state guy. I currently run a pair of Ayre MX-R Twenties that I truly love and respect. But I've never heard a tube amp in my system, and I thought It might be a fun winter project. I'm leaning toward the ARC Reference 150. I figure if I like it enough to keep it, I could always get the SE upgrade when it needs tubes.

Hi imgoodwithtools
If you’ve got the dough, go Ref 150 se or GS 150. I have a Ref 150 which I purchased when it came out. I later dropped KT 150s from ARC into the unit to obtain what I have been told by ARC insiders gets me 90% of the way to a Ref 150 se. The Kt 150s were a noticeable improvement but not as noticeable as when I went from my Ref 110 to my Ref 150 which was huge. If I were buying from scratch, I’d buy the GS 150 or Ref 150se. I believe some members here have compared the 2 and preferred the GS 150 by a slight margin. Scroll around and I’m sure you’ll find those comparisons.
OTOH, the Ref 150 is a great amp with KT 120s. If the price is right, consider purchasing the unit with KT 120s and  and replacing them with KT 150s in the future so the cost can be spread out. I assure you that all of the above options will provide you with great satisfaction.

I can solder. What is the mod?

ARC is the best a classic for sure wonderful sound as well.

The 150 is a classic amp that can be modified to sound like one of the best.  Do you know how to solder?

The "darkness" perceived as house sound in BAT VK75 & VK150 amps is largely a consequence of the Jensen PIO coupling caps. Light, speed, and precision is let in by replacing those caps. It’s a simple, economical, and effective upgrade.

Correction: until I spend time w/ the ARC ref6, the Ref5SE is the finest pre-amp.

OP-
go for the "SE" upgrade. I will add that until i spend time w/ the ARC Ref5SE
pre-amp, it is the finest.

B.A.T. is on my demo list as soon as I find a dealer/retailer. Happy Listening!

I have a line on a used ARC Reference 150 for a reasonable price. If I like it, I could get it upgraded to an SE for $5K more. I wonder how substantial the SE upgrade is?

The house sound from BAT tends to be a bit darker than ARC. The criticism of BAT is that it's a bit on the dark side. Criticism of ARC is it's not "tubey" enough. I happen to disagree with both criticisms. I'm a big ARC amp fan, especially over the last 5 years or so starting with the Ref 150 amp. On the other hand, I have not not heard a BAT product that I did find alluring with a dash of that darkness that can sound seductive. Both companies stand behind their product. You can't go wrong. 
But as for the Ref 150se or GS 150, these are the 2 best amps in that power range that I have ever heard. These are very special amps.